Phosphines



United States Patent 3,086,056 PHOSPHINES Ross I. Wagner, Montebello,Calif., assignor to American Potash & Chemical Corporation, acorporation of Delaware No Drawing. Original application Nov. 8, 1957,Ser- No. 695,241. Divided and this application July 8, 1960, Ser. No.44,491

13 Claims. (Cl. 260-6065) This invention relates in general to thepreparation of phosphines which contain more than a single phosphorusatom, and phosphines which have a heterocyclic ring which includes thephosphorus atom itself. This application is a division of applicantsco-pending U.S. patent application, eri-al No. 695,241, filed November8, 1957.

An object of this invention is to provide a method for the preparationof primary and secondary difunctional phosphines, phosphines whichcontain more than a single phosphorus atom, and secondary heterocyclicphosphines which are phosphines having a heterocyclic ring including thephosphorus atom itself, the process being suitable for producing thesetwo novel types of chemical compounds substantially individually or inadmixture.

A further object of this invention is to provide new chemical compounds,difunctional phosphines which contain more than a single phosphorus atomand phosphines which contain a heterocyclic ring having a phosphorusatom incorporated therein, these new chemical compounds being useful, asset forth in our copending applications, Serial No. 666,213, filed June17, 1957, now Patent No. 2,925,440 for Phosphinoborine Compounds andTheir Preparation and Serial No. 666,208, filed June 17, 1957, nowPatent No. 2,926,194 for Phosphine Borine Compounds and TheirPreparation.

Other objects and advantages of this invention, if not specifically setforth, will become apparent during the course of thediscussion whichfollows.

Generally, it has been found that phosphines containing the phosphorusin a heterocyclic ring and difunctional phosphines, may be obtainedwhere phosphine or' a primary organo-phosphine and an alkali metal arereacted under certain conditions and the reaction product so prepared isthereafter treated with an alkyl dihali-de. Individual products arereadily isolatedwherever the heterocyclic and difunc-tional material aresecured in admixture. More particularly, the preparation of certainphosphines containing the phosphorus in aheterocyclic ring and/orphosphines which are difunctional, i.e., having more than a singlephosphorus atom within a molecule, may be accomplished as follows:

Equal molar quantities of phosphinetPH or a primary organo-phosphine(RPH and an alkali metal are reacted, the phosphine material beingpassed into a stirred solution of the alkali metal dissolved inrefluxing ammonia until the blue color is replaced by the yellow colorof MPH or MPHR, where M is an alkali metal. In the preferred embodimentof this invention, R represents phenyl, lower alkyl-substituted phenyland halo-substituted phenyl. Lithium, potassium and sodium are thepreferred alkali metals for use in the process because of theiravailability-but the other alkali metals will serve satis- I having theformula p ICQ factorily also. Preferably, the by-product H is ventedthrough a mercury bubbler to prevent access of air to the interior ofthe apparatus. Other suitable means for iemoving the hydrogen from thereaction vessel and preventing access of air are known to the art andmay be employed. An alkyl dihalide having the general formula (CH Xwhere n is one to seven and wherein X represents a halogen, is thenadded to the contents of the reaction vessel until the yellow color isdischarged. The alkyl dihalide may be added as rapidly as permitted bythe apparatus used-limited only by the capacity of the reflux condenserto return volatilized solvent to the reaction vessel. The product, ifsufficiently volatile at 33 C., is azeotropically distilled from thereaction mixture with the solvent and then freed of residual ammonia bypassing the immiscible product layer through a suitable material foradsorption of the ammonia. Suitable materials are water or anhydrouszinc sulfate at 0 C. The product is then purified by distillation. Thisprocedure for separating the solvent and the product is suit-able if thedesired product is sufficiently volatile at the boiling point ofammonia, 33 C. However, where the prodnot is high boiling, it isdistilled from the reaction vessel after evaporation of the solvent andthereafter purified by fractional distillation.

A mixture of products is secured by the reaction, one of which is a'difunctional phosphine having the formula (CH (-PH wherein n is aninteger varying from 3 through 7, and the other is the secondaryheterocyclic phosphine, the ring including the phosphorus atom, havingthe formula CH:1(CH2) n-iPH when the phosphorus containing reagent isphosphine.

When a primary organo-phosphine is used as thephosphorus-containing.reagent, the two products are a difunctionalsecondary phosphine having the formula (CH ,(PHR) and the heterocyclictertiary phosphine Here, the symbol R may represent an aliphatic oraromatic radical. The cyclic and difunctional materials may then beseparated by fractional distillation, the cyclic phosphine beingvolatilized first.

The preparative reactions are represented by the following generalequations,

where R is either hydrogen or an organic radical, M is an alkali metal,X is a halogen, and n is an integer indicative of the number ofmethylene groups in the alkyl dihalide.

The preparation of the unsymmetrically substituted difunctionalphosphines is accomplished by first preparing the compound R(PH as setforth in the examples which follow and thereafter forming a metal salton one P. Thereafter the compound is alkylated with RX to make H PRPHR.The procedure is repeated on the other phosphorus atom and it isalkylated with R"X to yield R"HPRPHR' wherein R' and R" are aliphaticradicals.

Examples of the preparation of cyclic phosphines and difunctionalphosphines are set out below.

Example 1.-Phosphine in the amount of 0.717 g. (0.0211 mole) wascondensed into a tube containing 0.4847 g. (0.02108 mole) Na dissolvedin a 15 ml. quantity of ammonia. After the blue color of the solutionwas replaced by the yellow color of sodium phosphinide, a quantity of1.3152 g. (0.01035 mole) of (CH Cl was then added causing the yellowcolor to disappear from the react-ion mixture. External cooling was usedto maintain the reaction temperature in the range 78 C. to 33 C. Theproduct was relatively non-volatile at the boiling point of ammonia, 33C. The products were freed of ammonia by fractional distillation. Amixture of products was secured, 0.57 54 g., or a yield of 45.5 percentof (CH (PH (B 25 C.) and 0.4129 g., or a yield of 45.3 percent of (BC.). The heterocyclic ring phosphine material was separated from thedifunctional phosphine by distillation under vacuum with a fractionaldistillation column having a vapor take-off head.

Example 2.Phosphine was passed into a stirred solution of 1.0 mole Nadissolved in 1 liter of refluxing ammonia until the blue color wasreplaced by the yellow color of NaPH The by-product H was vented througha series of cold traps to catch unreacted and by-product phosphine and amercury bubbler was used to prevent access of air into the apparatus.Thereafter, liquid (CH Br in a molar ratio of one mole to each two molesphosphine employed was added to the refluxing mixture until the yellowcolor formed by the interaction of the phosphine and sodium disappeared.The product had a boiling point somewhat higher than that of the ammoniaand therefore it was necessary to evaporate the solvent first. Theproduct was finally purified by fractional distillation. The product wasa mixture of 2)7( 2)2 and These two compounds were separated byfractional distillation.

Example 3.--A solution was prepared of 4.11 moles Na in 1.5 liters ofrefluxing ammonia (33 C.) and thereafter 4.21 moles phosphine, PH wasadded. The sodium was used in a weight of 95.4 g. and 143 g. of thephosphine were needed. In accordance with the method set forth inExample 2 above, the by-product H was passed through a series of trapsand the unreacted PH removed. A total of 263 g. or 2.07 moles of (CH Cl4 was added at the rate dictated by the capacity of the refiuxcondenser. The yellow color of the mixture disappeared toward the end ofthe addition. The products were separated from solvent and from eachother by fractional distillation. Quantities of 39.9 g. of

or 15.8 percent, and 119.5 g.

or 65.7 percent were obtained.

Example 4.Sodium phosphinide was prepared by the direct exothermicreaction of 0.6032 g. (0.0262 mole) sodium with 0.891 g. (0.0262 mole)phosphine in 8 ml. liquid ammonia at 78 C. in a 1 inch diameter heavywall Pyrex bomb tube of ml. volume. A 1.3047 g. (0.0132 mole) sample ofethylene dichloride was added to the tube at 196 C. and the mixture inthe sealed tube was warmed to room temperature for 20 minutes. The bombtube was then opened and the volatile products were distilled into a 15ml. centrifuge cone. The immiscible lower layer of product wasmechanically separated from the solvent ammonia and purified byfractional condensation. Physical properties of the product weredetermined as follows: Molecular weight, 60.0; M.P., -121.4 to 120.9 C.;vapor pressure equation, log P ==7.753-1509/T. A non-volatile viscousliquid formed on standing at ambient temperatures.

The cycloethylenephosphine formed according to the following equation:

/PH PHa 2Na01 CH;

Example 5.-A solution was prepared of 27.1 g. sodium (1.18 moles) in 1liter of refluxing ammonia and thereafter 47 g. of phosphine (1.38moles) was added. The by-product H was passed through a series of trapsand the unreacted PH removed. A total of 69.2 g. (0.612 mole) of (CH Clwas added at a rate dictated by the capacity of the reflux condenser.The yellow color of the mixture disappeared toward the end of theaddition and the product was isolated after distilling the solvent fromthe reaction mixture. The product was freed of residual ammonia bypassing it through anhydrous zinc sulfate at 0 C. and was then purifiedby distillation. Fractional distillation was used to separate theproducts of the reaction, and the yield of (CH (PH was determined to be14.3 g. or 23.0 percent.

Example 6.Substantially in the manner set forth in Example 5 above, 26.5g. (1.15 moles) sodium were reacted with 41 g. (1.20 moles) phosphineand thereafter this product treated with 115.7 g. (0.573 mole) of (CH Br34.7 g. (CH (PH a 56 percent yield, was obtained.

Example 7.--In the fashion set forth above, 31.8 g. (1.38 moles) sodiumwere reacted with a 47.7 g. phosphine (1.40 moles) phosphine inrefluxing ammonia and thereafter this product treated with 213.9 g.(0.69 mole) of (CH I The products, (CH (PH and were isolated inaccordance with the methods set forth above.

The stoichiometry for further typical runs is set forth below:

Table I Reagents Products Ex: Alkali metal RPH: (GHQDX CHz(CHl)n-1PR M R(OHflnX, (0H,)..(PHR), I I

Weight, Moles Weight, Moles Weight, Moles 10 Na 0.4205 0.01829 0211s1.135 0.01829 (CH2)4C1:.. 1.16 0.00916 (CH2)4(PHG:H CHQ(CH2)3POZH5 l I11-- Na 2.38 0.103 l-CaHv 8.0 0.105 (CH2)4B1:.. 10.58 0.049(CH=)4(PH-l-O H GH2(CHg)31| -l-C3H1 12-- Na 0.3797 0.01650 n-C Hn 1.7140.01648 (CHMCIL. 1.156 0.00820 (CHl)5(PH-11-C5Hu)g CH2(CH2)4P'1'1'C5H1113-- Na 0.3396 0.01477 i-C4Hs 1.320 00146 95012.. 1.037 0.00735(CHz)s(PH-l-O H CH (CH P-l-C H 14-- Na 0.3038 0.01320 n-CaHu 1.9390.01326 (CHa)4C12 0.845 0.00665 (CHz)4(PH-n-OsHi1)2 CHs(CH2)aP-n-O3H115-- Na 23.0 1.00 on. "48 1.00 (011mm... 102.0 0.505 (oH PHom 16-- Na 0.6496 0.02824 CH3 1.835 0.02821 (01101011-- 13911001405 CHQGHZPCHB 17--No 230 1.00 CH3 -.49 1.02 1104011-- 66.0 0.52 (CH2)4(PHGH CH5(CH:)3PCH318-- K 2.627 0.0672 P-GnHsCcH; 9.228 0.0668 05 12. 4.683 0.0332 2) (I 25 fl 2( H2)4P(p- 2Hs o 4) 012. I 19 L1 0.3255 0.0469 OBHE 5.212 00473(01101011.. 3.991 0.0236 (OH2)7(PHO0H5)3 OH2 0IIZ 6PCBH5 20-- Na 0.71750.0312 C H CH 8.926 0.0316 (C z)uCh 2.388 0.0154 (OH2)0[PH(CH200H5)]ZCH2(OH2)5PCH200H5 21-- K 0.6294 0.0161 p-ClUuH4 2.284 0.0158 (0119 01 00.9780 0.00769 (CH2)4[PH(D'O1COH4)]2 OHi(CHi)sP(p-C1C Hl) 22 Na 0.27780.01208 C6H5 1.3268 0.01205 (CHmIz.-- 1.776 0.00600 (CH)=(PHO H 23-- Na0.7975 0.03468 p-CHaCfl-l; 4.310 0.03472 (OHzhCl 2.2025 0.01734(OH2)4[PH(p-OH;O CHz(OH2)QP(P-CH3C H 012. I I 24-- Na 2.534 0.11022,4,6-(CH O H1 16.832 0.1106 (CH2)4Ch 6.999 0.0551 (CH2)4PH[(CHs)aOoCH2(CH2)3P[(CH3)3CQH9] H212. I I 25-- Na 0.8854 0.0385 p-BrCoHt 7.2040.0381 (CH2)5Brz.. 4.354 0.0189 (CH;)5[PH(p-BrCsH4)]2CHz(CH2)4I"(p-BICsH4) Example 8.2.384 g. (49.64 mmoles) CH PH was addedto a ml. reaction flask cooled to -78 C. containing 35 ml. liquidammonia and sodium amide, prepared from 1.1415 g. (49.64 mmoles) sodium.To the re sulting solution of sodium methylphosphinide, CH PHNa, wasadded 4.320 g. (50.85 mmoles) CH Cl After 30 minutes reaction time at-78 C., the solvent and volatile products were distilled from theby-product sodium chloride and separated by fractional distillation.Bis- (methylpho-sphino)methane, (CH HP) CH was isolated by removalthrough a vapor take-01f distilling head at -20 to 15 .C. under highvacuum. The product, which was unstable at ambient temperatures, meltedover the range 20 to l3 C. and had a molecular weight 102.2 (calc.108.07).

Example 9.-qA solution was prepared of 1.37 moles (31.8 g.) Na in 0.5liter refluxing ammonia (33 C.) and 1.47 moles (47.7 g.) phosphineadded. As described in Example 2 above, the by-product H was passedthrough a series of traps and the unreacted PH removed. A quantity of97.3 g or 0.69 moles of (CH C1 was added at a rate appropriate for thesize reflux condenser selected. The yellow color of the mixturedisappeared toward the end of the addition. The products were separatedtrom the solvent and from each other by fractional distillation. Goodyields of (CH (PH and were secured.

+R"HPRPHR+R'HPRPHR'+8MX Method 2 for the preparation of theunsymmetrically substituted difunctional phosphines gives a theoretical50 percent yield of the unsymmetrically substituted product and, to beuseful, the three products must be separable by means such asdistillation, where the R and -R must be of considerably dilferentmolecular weight, or by fractional crystallization.

Examples setting forth the stoichiometry of typical reactions for thepreparation of these primary-secondary difunctional phosphines andcertain of unsymmetrically substituted secondary difunctional phosphinesappear below.

Table II Alkali metal Alkylhalide Weight, En M Phosphlne Moles g. RXProduct Moles Weight, Moles Weight,

0. 0723 1. 663 (CH (P112): 0. 0732 8. 937 0211501 4. 648 Hz]?(CH2)4PHC2H5 O. 0607 1. 396 ECH2)3(PH2)2- 4. 877 H11 (CH7)3PII(l1-C3H7)O. 0421 O. 968 CH2)0(PH2)2 2. 639 HQP(OHZ)OPHC2 5 O. 0598 2. 338(CH2)a(PHz)z-- 3. 019 H2P(CH2)3PHCH 0.0312 0.718 M (PH 2. 953 HaP (G 2)4a 0. 0561 0.389 (CH2)4(PH2)2. 8. 670 HzP (CHfl)4PH(l1-C5H1l) 0. 0626 1.440 (CH3)3(PH2)2- 12. 758 H21 (CH2) aPH (ll-012E11 O. 0491 1.129(CH2)3(PH2)2 7.270 HnP (CHzhPH (I1- 3H 0. 0386 0. 888 E21 (CHMPH 2115".3. 165 nCaH7HP(OHa)4PHCzH 0. 0573 1. 318 HzP(CH2)aPH (ll-C3117) 3. 620C2H5HP(CH2)3PH (II-C311 0. 0379 0. 872 H21 (CH2)4PHC2H5 1. 843 CHQHP(CHz)4PI-IC2H5 O. 0280 0. 644 H1P(CI'I2)aPHCHa 1. 813 C2H5HP(CH2) 3PHCHO. 0192 0. 751 2P (CHg) PHCH 1. 641 II-C3H1HP(CH2)3PHCH3 0. 0473 1. 088Hz]? (GH2)4PH (11-C5Hu) 2. 424 CHaHP (CH1)4PH (n-C5Hu) 0. 0550 l. 265H2P(OH:) PH(11 5. 279 CH3HP(CH2)aPH(n-C12H25) O. 0481 1. 1061:11P(CH7)aPH(n-CsH17)--- 0. 0481 0111 01- 3. 155 CzH HP(CHg)3PH(n-C HObviously many modifications and variations of the invention asherein'before set forth may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claims.

I claim:

1. The difunctional phosphine (CH (PHR) where R is selected from thegroup consisting of H, alkyl, phenyl, lower alkyl-substituted phenyl andhalo-substituted phenyl radicals and n is an integer from three toseven.

2. The difunctional phosphine (CH (PH 3. The difunctional phosphine (CH(PH The difunctional phosphine (CH (PH The difunctional phosphine (CH(PHCH The difunctional phosphine (CH (PHC H The difunctional phosphineCH (PHCH The difunctional phosphine 9. The difunetional phosphine (CH[PH(ClC I-I 10. The difunctional phosphine (CH (PHC H 11. Thedifunctional phosphine 12. The difunctional phosphine'(CH2)4[PH(CH3)3C6H2]2 13. The difunctional phosphine References Citedin the file of this patent UNITED STATES PATENTS Morris et a1.

June 16, 1953 OTHER REFERENCES Beilstein: Handbuch der organischenChemie, vol. 4,

1. THE DIFUNCTIONAL PHOSPHINE (CH2)N(PHR)2 WHERE R IS SELECTED FROM THEGROUP CONSISTING OF H, ALKYL, PHENYL, LOWER ALKYL-SUBSTITUTED PHENYL ANDHALO-SUBSTITUTED PHENYL RADICALS AND N IS AN INTEGER FROM THREE TOSEVEN.